The present invention relates to a manufacturing method of a semiconductor device and a semiconductor device and, in particular, to a manufacturing method of a semiconductor device having a Cu—Ni wiring and to technology effective when applied to a configuration of a semiconductor device having a Cu—Ni wiring.
A semiconductor device has semiconductor elements, such as MISFETs, formed over a semiconductor substrate and wirings in multiple layers formed above the semiconductor elements. Then, over the uppermost layer wiring, for example, a rewiring including a Cu—Ni wiring is formed. One end of the rewiring serves as a coupling part coupled with the uppermost wiring and the other end of the rewiring serves as a pad region. In this manner, the rewiring plays a role in coupling the end part of the uppermost layer wiring and a pad region in a predetermined position of a semiconductor chip.
For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2005-38932) described below, a semiconductor device having a rewiring layer is disclosed and manufacturing technology of a semiconductor device having steps as shown in (1) to (5) below when forming the rewiring layer is disclosed (in particular, see paragraphs [0072] to [0077] in Patent Document 1).
(1) By applying a first photosensitive resin over a base metal layer [6b] and exposing and developing it, a first photosensitive resist [11a] is formed in the part excluding the formation part of a main conductor layer [6a] [FIG. 2(d)]. After forming the first photosensitive resist [11a], it is temporarily cured [FIG. 2(e)].
(2) By utilizing the first photosensitive resist [11a], the main conductor layer [6a] is formed. Specifically, by performing electrolytic plating using, for example, a copper plating liquid including copper sulfate, the main conductor layer [6a] including Cu is formed in an opening of the first photosensitive resist [11a] [FIG. 2(f)]. After that, the first photosensitive resist [11a] is removed [FIG. 2(g)].
(3) By applying a second photosensitive resist over the main conductor layer [6a] and exposing and developing it, a second photosensitive resist [11b] is formed so that only the upper surface or the surface of the main conductor layer [6a] excluding a part of the main conductor layer [6a] is exposed, which is exposed because a metal pillar [9] is formed. After that, it is temporarily cured [FIG. 2(h)].
(4) Then, by utilizing the second photosensitive resist [11b], a metal layer [7] is formed. Specifically, a Ni layer having a film thickness of 1 μm to 3 μm is formed in the opening of the second photosensitive resist [11b] by, for example, the electrolytic plating method. After that, the second photosensitive resist [11b] is removed by a stripping solution.
(5) Next, the following processing is performed by using, for example, an etchant including ammonium persulfate as a principal component and an etchant including a hydrogen peroxide solution and inorganic ammonia as principal components and desirably, including an additive having a function to protect the main conductor layer [6a] against the etchant by temporarily forming a surface protection layer on the main conductor layer [6a]. The base metal layer [6b] in the part other than the rewiring layer, that is, in the part where the metal layer [7] is not formed and the barrier metal layer [5] located under the part are removed by etching [FIG. 3(j)]. Those inside [ ] are symbols or figure numbers described in Patent Document 1.